name: ghc-typelits-knownnat
version: 0.5
synopsis: Derive KnownNat constraints from other KnownNat constraints
description:
A type checker plugin for GHC that can derive \"complex\" @KnownNat@
constraints from other simple/variable @KnownNat@ constraints. i.e. without
this plugin, you must have both a @KnownNat n@ and a @KnownNat (n+2)@
constraint in the type signature of the following function:
.
@
f :: forall n . (KnownNat n, KnownNat (n+2)) => Proxy n -> Integer
f _ = natVal (Proxy :: Proxy n) + natVal (Proxy :: Proxy (n+2))
@
.
Using the plugin you can omit the @KnownNat (n+2)@ constraint:
.
@
f :: forall n . KnownNat n => Proxy n -> Integer
f _ = natVal (Proxy :: Proxy n) + natVal (Proxy :: Proxy (n+2))
@
.
The plugin can derive @KnownNat@ constraints for types consisting of:
.
* Type variables, when there is a corresponding @KnownNat@ constraint
.
* Type-level naturals
.
* Applications of the arithmetic expression: +,-,*,^
.
* Type functions, when there is either:
.
1. a matching given @KnownNat@ constraint; or
.
2. a corresponding @KnownNat\<N\>@ instance for the type function
.
To use the plugin, add the
.
@
OPTIONS_GHC -fplugin GHC.TypeLits.KnownNat.Solver
@
.
Pragma to the header of your file.
homepage: http://clash-lang.org/
license: BSD2
license-file: LICENSE
author: Christiaan Baaij
maintainer: christiaan.baaij@gmail.com
copyright: Copyright © 2016 , University of Twente,
2017-2018, QBayLogic B.V.,
2017 , Google Inc.
category: Type System
build-type: Simple
extra-source-files: README.md
CHANGELOG.md
cabal-version: >=1.10
tested-with: GHC==8.0.2, GHC == 8.2.2, GHC == 8.4.1, GHC == 8.4.2,
GHC == 8.5.0
source-repository head
type: git
location: https://github.com/clash-lang/ghc-typelits-knownnat.git
flag deverror
description:
Enables `-Werror` for development mode and TravisCI
default: False
manual: True
library
exposed-modules: GHC.TypeLits.KnownNat,
GHC.TypeLits.KnownNat.Solver
other-modules: GHC.TypeLits.KnownNat.TH
other-extensions: AllowAmbiguousTypes
DataKinds
FlexibleInstances
KindSignatures
LambdaCase
MultiParamTypeClasses
ScopedTypeVariables
TemplateHaskell
TupleSections
TypeApplications
TypeOperators
TypeFamilies
TypeInType
UndecidableInstances
ViewPatterns
build-depends: base >= 4.9 && <5,
ghc >= 8.0.1 && <8.6,
ghc-tcplugins-extra >= 0.3,
ghc-typelits-natnormalise >= 0.6 && <0.7,
transformers >= 0.5.2.0 && <0.6,
template-haskell >= 2.11.0.0 && <2.14
hs-source-dirs: src
default-language: Haskell2010
if flag(deverror)
ghc-options: -Wall -Werror
else
ghc-options: -Wall
test-suite test-ghc-typelits-knownnat
type: exitcode-stdio-1.0
main-is: Main.hs
Other-Modules: TestFunctions
build-depends: base >= 4.8 && <5,
ghc-typelits-knownnat,
ghc-typelits-natnormalise >= 0.6 && <0.7,
tasty >= 0.10,
tasty-hunit >= 0.9,
tasty-quickcheck >= 0.8
hs-source-dirs: tests
default-language: Haskell2010
other-extensions: DataKinds
FlexibleContexts
FlexibleInstances
GADTs
MultiParamTypeClasses
KindSignatures
ScopedTypeVariables,
TemplateHaskell
TypeApplications
TypeFamilies
TypeFamilyDependencies
TypeOperators
UndecidableInstances
if flag(deverror)
ghc-options: -O0 -dcore-lint